1. Field of the Invention
The present invention relates to webbing locking devices used in seatbelt systems for locking an occupant restraining webbing when necessary, and more particularly to a webbing locking device adapted to directly lock the intermediate portion of the webbing.
2. Description of the Prior Art
In general, seatbelt systems are used to restrain an occupant with an occupant restraining webbing for protecting him in an emergency such as a collision of a vehicle. There has been proposed a webbing locking device in which such consideration is given that the intermediate portion of the webbing is directly clamped during a vehicular emergency whereby the webbing is prevented from extending and the webbing loosely wound into the retractor is prevented from being tightened, so that the occupant can remain in a perfectly restrained condition.
In the webbing locking device of the type described, a rotatable plate is pivotally supportd on a frame, the webbing is guided around the forward end portion of the rotatable plate to transmit a tensional force of the webbing in an emergency of the vehicle as a pivotally moving force of the rotatable plate, whereby this pivotally moving force is utilized to directly clamp the intermediate portion of the webbing by clamping means, so that the webbing can be prevented from moving in the longitudinal direction thereof.
A roller is provided at a webbing contact portion of this rotatable plate for the purpose of decreasing a resistance against the movement of the webbing. However, tensional forces of the webbing in front and at the back of the webbing contact portion of the roller are substantially equal to each other when the windout of the webbing is stopped, whereby no decrease of tension in the webbing occurs at the webbing contact portion of the roller, thus presenting such disadvantages that the webbing cannot be positively clamped at the clamped portion thereof or the webbing may be broken at the clamped portion thereof.